U.S. patent number 4,497,339 [Application Number 06/408,549] was granted by the patent office on 1985-02-05 for two-stage pressure regulator.
This patent grant is currently assigned to The Gillette Company. Invention is credited to Walter J. Diederich, George P. Gruner.
United States Patent |
4,497,339 |
Gruner , et al. |
February 5, 1985 |
Two-stage pressure regulator
Abstract
A two-stage fuel regulator, adapted for operation in any
orientation and over a wide temperature range, which includes a
pressure limiter, a fuel vaporizer, a low pressure cutoff and an
on/off switch. The first stage includes an inlet from a fuel
storage tank where the fuel is maintained in a two-phase system of
liquid and vapor. The tank inlet opens to one side of a diaphragm
having a throughgoing hole surrounded by an annular valve face. A
space on the other side of the diaphragm defines an expansion
chamber. By adjusting the biasing force with which the valve face
abuts a valve seat, the expansion chamber pressure may be
maintained to be less, by a predetermined pressure difference
(e.g., 1 psi), than the tank pressure, whereby vaporization of all
fuel in the expansion chamber is assured. Additionally, whenever
the tank pressure drops below the predetermined pressure difference
(e.g., when the fuel supply is low or in a cold environment),
passage of fuel into the expansion chamber is prohibited. The
second chamber contains a second biased diaphragm coupled to an
additional valve face and seat to limit the pressure at which gas
is supplied for consumption. The additional valve face and seat may
be manually controlled through an on/off switch.
Inventors: |
Gruner; George P. (Andover,
MA), Diederich; Walter J. (W. Newbury, MA) |
Assignee: |
The Gillette Company (Boston,
MA)
|
Family
ID: |
23616726 |
Appl.
No.: |
06/408,549 |
Filed: |
August 16, 1982 |
Current U.S.
Class: |
137/495;
137/505.12; 431/89 |
Current CPC
Class: |
F21L
19/00 (20130101); Y10T 137/7782 (20150401); Y10T
137/7795 (20150401) |
Current International
Class: |
F21L
19/00 (20060101); F16K 031/14 () |
Field of
Search: |
;431/89,12
;137/505.12,495 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Green; Randall L.
Attorney, Agent or Firm: De Vellis; Raymond J.
Claims
What is claimed as new and desired to be secured by Letters Patent
of the United States is:
1. A regulator particularly adapted for use in a hand-held device
powered by liquefied gas, comprising:
a first chamber having a fuel inlet port;
a first diaphragm dividing said first chamber into upstream and
downstream compartments, said upstream compartment being in fluid
communication with said fuel inlet port;
first valve means for maintaining a predetermined pressure
difference between said upstream and downstream compartments;
a second chamber having a fuel outlet port and including a second
diaphragm;
second valve means for establishing fluid communication between
said downstream compartment and said second chamber whenever the
pressure in said second chamber falls below a predetermined level
and for blocking fluid communication between said downstream
compartment and said second chamber whenever the pressure in said
second chamber equals or exceeds said predetermined level;
positive shutoff means for blocking fluid communication between
said downstream compartment and said second chamber, independent of
the pressure in said second chamber; and
first adjusting means for adjusting said predetermined pressure
difference.
2. The regulator of claim 1, further comprising second adjusting
means for adjusting said predetermined level.
3. The regulator of claim 2, wherein said first valve means
comprises a throughgoing aperture in said first diaphragm, a first
valve face surrounding said aperture, a first valve seat disposed
within said upstream compartment and first biasing means for
biasing said first valve face against said first valve seat.
4. The regulator of claim 3, wherein said second valve means
comprises a passageway between said downstream compartment and said
second chamber, a second valve seat surrounding the termination of
said passageway in said downstream compartment, a second valve face
disposed within said downstream compartment, said first biasing
means also biasing said second valve face against said second valve
seat, and means for displacing said second valve face away from
said second valve seat whenever the pressure in said second chamber
falls below said predetermined level.
5. The regulator of claim 4, wherein said displacement means
comprises a valve stem connected to said second valve face,
extending through said passageway and terminating adjacent said
second diaphragm, such that movement of said second diaphragm
toward said passageway displaces said second valve face away from
said second valve seat.
6. The regulator of claim 5, wherein said first adjusting means
comprises a threaded plug and a corresponding threaded opening in
said upstream compartment, said first valve seat being mounted on
said threaded plug.
7. The regulator of claim 6, wherein said second adjusting means
comprises a second biasing means for biasing said second diaphragm
toward said valve stem and means for varying the force exerted on
said second diaphragm by said second biasing means.
8. The regulator of claim 7, wherein said positive shutoff means
comprises means for moving said second diaphragm away from said
valve stem.
9. The regulator of claim 8, wherein said movement means includes
an elongated member attached to said second diaphragm.
10. The regulator of claim 9, wherein said first biasing means is a
spring member.
Description
BACKGROUND OF THE INVENTION
1. Field of the Invention
This invention relates to a hand-held lighting device (e.g., a
flashlight), wherein light is radiated from a mantle which is
heated to incandescence by the combustion of a gaseous fuel such as
isobutane.
More particularly, the invention relates to a fuel regulator
particularly adapted for use in such a hand-held lighting
device.
2. Description of the Prior Art
Valves for regulating the delivery pressure of a gaseous fuel are
well known in the art.
In a hand-held device powered by liquefied gas, it is advantageous
to employ a regulator which will deliver fully evaporated fuel at a
specified pressure, regardless of the tank pressure, ambient
opreating termperature or orientation of the device.
An ordinary needle valve is subject to the limitation that its
delivery pressure varies in accordance with the fuel tank pressure,
and thus a needle valve must be constantly readjusted in accordance
with the ambient temperature. In a portable unit, which may be used
in various orientations the problem is aggravated, since if
inverted, a needle valve has a tendency to pass liquid fuel,
resulting in a sputtering and erratic flame.
A number of pressure regulators are known in which a biased
diaphragm is coupled to a variable valving mechanism. Varying the
bias on the diaphragm controls the delivery pressure. Examples of
this type of pressure regulators are to be found in Webster, U.S.
Pat. Nos. 2,793,504 and 2,854,991; Baranowski, Jr., U.S. Pat. No.
3,699,998; Bowman et al, U.S. Pat. No. 3,736,093; Fleischacker et
al, U.S. Pat. No. 3,812,877; and Curtis, U.S. Pat. No.
3,941,554.
Under normal operating conditions, the above-described type of
pressure regulator achieves the object of supplying gaseous fuel at
a prescribed delivery pressure, independent of the tank pressure.
However, at low temperatures, when the fuel tank pressure falls
below the delivery pressure, this type of regulator will deliver
unvaporized fuel, if the device in which it is employed has been
inverted.
Another known type of flow control element employs a porous plug
interposed in the fuel stream, which retards the flow and induces a
pressure drop, thereby evaporating the fuel.
For example, in Baumann et al, U.S. Pat. No. 3,388,962, there is
shown a portable torch in which a sintered metal plug is provided
upstream of a needle valve.
Similarly, Tissot-Dupont, U.S. Pat. No. 3,183,686, discloses a
compressible porous element positioned in the fuel supply stream.
The porosity of the element may be adjusted by varying the degree
of compression to which it is subjected.
Like needle valves, the delivery pressure provided by such porous
flow retarders varies with the ambient temperature. Additionally,
porous flow retarders do not completely overcome the problem of
liquid fuel passage at low temperatures.
Another approach to preventing the passage of liquid fuel is shown
in Benzaria, U.S. Pat. No. 3,955,913, in which a miniature torch,
designed to be held in the hand like a pencil, has a fuel feed tube
which extends to the center of the fuel tank, which is then filled
to slightly less than half full. Such an arrangement unduly limits
the fuel capacity of a given device and is vulnerable to sudden
movements.
Considering that passge of liquid fuel is most likely when the tank
pressure is extremely low, due to low operating temperatures, it is
desirable to provide a low pressure cutoff.
In Yost et al, U.S. Pat. No. 3,118,494 and Kinsella et al, U.S.
Pat. No. 3,711,236, there are shown low pressure cutoff devices
employing solenoids energized by thermocouples deployed adjacent
pilot burners. These devices are relatively expensive, complicated,
and best suited for use in gas-fired water heaters and the
like.
RELATIONSHIP TO OTHER APPLICATIONS
The aspirated pilot burner structure and associated ignition
assembly described herein are claimed in a separate application
(Ser. No. 408,551), now U.S. Pat. No. 4,475,882, by George P.
Gruner entitled "Gas Mantle with Aspirated Pilot Light", filed
concurrently with and assigned to the same assignee as the present
application.
Similarly, the shock-absorbent mantle structure described herein is
claimed in a separate application (Ser. No. 408,553), now issued,
by George P. Gruner entitled "Shock Mounting for Incandescant
Mantle, also filed concurrently with and assigned to the same
assignee as the present application.
In another related application (Ser. No. 408,511), now U.S. Pat.
No. 4,475,882, entitled "Gas Mantle Technology" by Walter J.
Diederich, also filed concurrently and assigned to the same
assignee as the present application, there is disclosed a
particularly fracture resistant mantle, a process for making the
mantle and a process for attaching the mantle to a mounting
structure.
The three above-identified related applications are hereby
expressly incorporated by reference.
SUMMARY OF THE INVENTION
To overcome the above-mentioned disadvantages, an object of the
present invention is the provision of a two-stage pressure
regulator, capable of delivering vaporized gaseous fuel at a given
pressure, regardless of orientation and over the entire operating
temperature range.
Another object of the present invention is to provide a simple and
reliable low pressure cutoff in such a regulator, thereby
preventing the passage of liquid fule at low operating
temperatures.
A still further object of the present invention is the provision of
a positive shutoff means in such a regulator.
In general, the invention features a regulator having a first
chamber with a fuel intake port; a first diaphragm dividing the
first chamber into upstream and downstream compartments, the
upstream compartment being in fluid communication with the fuel
inlet port; first valve means for maintaining a predetermined
pressure difference between the upstream and downstream
compartments; a second chamber having a fuel outlet port and
including a second diaphraghm; and second valve means for
establishing fluid communication between the downstream compartment
and the second chamber whenever the pressure in the second chamber
falls below a predetermined level and for blocking fluid
communication between the downstream compartment and the second
chamber whenever the pressure in the second chamber equals or
exceeds the predetermined level.
The above and other features of the invention will be made clear
through a description of a preferred embodiment, reference being
had to the accompanying drawings, wherein:
BRIEF DESCRIPTION OF THE DRAWINGS
FIG. 1 is a side elevational view, partially broken away, of a
gas-powered flashlight according to the invention;
FIG. 2 is a detailed sectional view of a two-stage fuel regulator,
provided in the flashlight of FIG. 1;
FIG. 3 is a front elevational view of the regulator of FIG. 2;
FIG. 4 is a sectioned elevational view of the central portion of
the flashlight of FIG. 1, showing a manual on/off switch mechanism
and an ignition mechanism thereof in greater detail;
FIG. 5 is a front sectional view of the flashlight of FIG. 1;
FIG. 6 is a sectioned elevational view of a mantle mounting
assembly of the flashlight of FIG. 1;
FIG. 7 is a perspective view of a deflection structure positioned
in both a mantle gas flow conduit and a pilot gas flow conduit of
the flashlight of FIG. 1;
FIG. 8 is a sectioned elevational view of another mantle mounting
assembly for use in the flashligh of FIG. 1;
FIGS. 9 (a), (b), (c) and (d) are sectioned elevational views of
the mantle mounting assembly of FIG. 8, displaced by the action of
various shock forces hereinafter described;
FIG. 10 is a sectioned elevational view of a pilot assembly of the
flashlight of FIG. 1; and
FIG. 11 is a sectioned elevational view of the ignition mechanism
of the flashlight of FIG. 1, showing the relative positioning of
the various elements thereof immediately following ignition.
DESCRIPTION OF THE PREFERRED EMBODIMENT
Referring now to FIG. 1, a disposable gas-powered flashlight,
indicated generally by reference numeral 10, is housed in a modular
housing assembly consisting of an extended octagonal housing
portion 12, a flared frustroconical housing portion 14 and a rear
end cap 16. Flared housing portion 14 is joined to housing portion
12 by radially disposed connecting pillars 18. Preferably, these
housing components are molded from a relatively high impact
plastic, such as Delrin.TM. and, in the disposable embodiment shown
and described, are permanently joined by one of a number of
conventional techniques well known in the art, such as press
fitting, spin welding, ultrasonic welding, etc.
An inwardly extending wall portion 17 serves to form a fuel chamber
24 in the rear interior of housing portion 12. A two-stage
regulator assembly 26 is generally disposed within fuel chamber 24
and projects through an opening in wall portion 17. A surrounding
O-ring 35 prevents leakage of fuel around regulator assembly
26.
In the disposable embodiment shown, fuel chamber 24 is adapted to
be charged with liquified gas during manufacture by the provision
of a fill plug 25 in end cap 16. In a refillable embodiment,
however, end cap 16 may be detachable from the remainder of the
housing assembly (e.g., through mating threads) to permit access to
a replaceable fuel tank disposed immediately interior thereof.
Alternatively, fill plug 25 could be replaced with a check valve
for recharging fuel chamber 24 from a conventional fuel
cannister.
Forward of wall portion 17, housing portion 12 generally encloses
the following assemblies: a manual on/off switch assembly 27, a
mantle assembly 28, a pilot assembly 30, and an ignition assembly
32.
A mantle 34 is mounted on the forward free end of mantle assembly
28 such that it projects into flared housing portion 14, where it
is disposed centrally of a spider-shaped heat shield 36 and an
essentially conventional parabolic reflector 38, both of which are
also enclosed within flared housing portion 14.
Mantle 34 may be of the well known type referred to as a Wellsbach
mantle, which consists of a thoria-ceria refractory produced by
impregnating a fiber sock with appropriate metal compounds and then
removing the fiber by oxidation.
Prior art mantles of this type have suffered from the drawback that
they are quite fragile. However, in the above-identified
application of Walter J. Diederich entitled "Gas Mantle
Technology", there is disclosed a process for manufacturing a
mantle which is significantly more fracture resistant than mantles
heretofore known. Preferably, mantle 34 is manufactured according
to the process taught by this application.
Still referring to FIG. 1, the forward end of flared housing
portion 14 is adapted to receive an annular rim 40 of a shock
absorbent material (e.g., rubber), which snaps over housing portion
14 and which is provided with a number of radially disposed slots
42. Rim 40 additionally serves to position a translucent lens 44
and a perforated metallic ring 46, having a maximum perforation
diameter of 1/25 of an inch, which encircles the interior of
housing portion 14 immediately adjacent slots 42. A second
perforated metallic ring 48, also having a maximum perforation
diameter of 1/25 of an inch, encircles the housing immediately
adjacent connecting pillars 18.
Heat generated during operation of the flashlight is effectively
carried away by air flowing through slots 42 and between connecting
pillars 18. The particular construction shown and described
promotes the formation of such convective air currents, regardless
of the flashlight's orientation.
It is known that an open flame cannot travel through a circular
restriction having a diameter of 1/25 of an inch or less or,
correspondingly, an unrestricted area of 0.00125 square inch.
Accordingly, perforated rings 46 and 48 provide the safety feature
of a flame arrestor means for confining the flame at mantle 34
within the housing assembly 12.
To obtain the brightest and hottest flame, mantle 34 is supplied
with an air/gas mixture. The air enters mantle assembly 28 through
a primary air intake 210 provided just downstream of regulator
assembly 26. For this purpose, housing portion 12 is provided with
a number of primary air intake ports 51. To eliminate the necessity
of having to provide additional flame-arresting means adjacent
primary air intake ports 51, and to provide an additional barrier
between mantle 34 and fuel chamber 24, an internal shield 50
encircling the interior of housing portion 12 is provided. Shield
50 is of generally dog-legged shape in cross-section and has a
lower portion which is disposed at a forwardly flaring oblique
angle with respect to both mantle assembly 28 and pilot assembly
30. Shield 50 encircles both mantle assembly 28 and pilot assembly
30. The interior terminal edge of shield 50 laps slidingly against
the exterior surfaces of mantle assembly 28 and pilot assembly 30
downstream of primary air intake 210. The flared shape of shield 50
and the sliding contact which it makes with mantle assembly 28 and
pilot assembly 30 accommodates transverse flexing of asesmblies 28
and 30 with minimum interference of these members, such as in
response to transverse shock forces. Additionally, such a sliding
contact presents an unobstructed area of less than 0.00125 square
inch. Accordingly, the interior of the housing assembly is
substantially divided, from a flame-arresting perspective, into
forward and rearward compartments, with the flame at mantle 34
confined to the forward compartment.
The construction and operation of the various assemblies referred
to above will now be described in more detail.
Regulator Assembly
It will be appreciated by those skilled in the art that a
gas-powered flashlight which may be employed in any orientation and
at various ambient temperatures raises special considerations
regarding the supplying of fuel to the active element, in this
case, mantle 34. In particular, the flow of liquid fuel to mantle
34 in an unvaporized state is undesirable, since such unvaporized
flow results in a fluttering and unreliable flame and, in general,
poor illumination. Moreover, if a sufficient amount of unvaporized
fuel were to reach mantle 34, a potentially hazardous flare-up
could occur.
In a gas-powered lighting device not specifically designed for
multiorientated operation, e.g., a conventional lantern,
unvaporized fuel flow is effectively prevented by the simple
expedient of locating the fuel feed at an upward portion of the
fuel tank. Since gaseous fuel under pressure normally exists in a
two-phase system of liquid and gas, with the liquid residing at the
bottom of the fuel tank and the gas being disposed thereover, such
an upwardly located fuel feed assures the supply of only vaporized
fuel, assuming the lantern is maintained upright. If inverted,
however, there is no assurance that all of the fuel supplied will
be completely vaporized, particularly at low operating
temperatures. This is in contrast to regulator assembly 26, shown
in detail in FIGS. 2 and 3.
Regulator assembly 26 generally includes a first stage 52 and a
second stage 54, both stages being contained within a
cylinder-shaped regulator housing 56. The rear face of housing 56
is open to provide access to its interior for the assembly of
various components therein, while the front face of housing 56 is
generally closed by a front wall 58, on which are integrally formed
an offset mantle mounting stud 60 and an offset pilot tube 62, and
through which passes a centrally located hole 64.
Holes 65 and 66, best seen in FIG. 3, pass through the central axes
of mantle mounting stud 60 and pilot tube 62, respectively, and
communicate with the interior of housing 56. Pilot tube 62 is
provided with a counter bore 67. Additionally, front wall 58 has
integrally formed therewith two cantilevered standards 68,68 having
arcuate bearing surfaces 70,70.
As will be discussed more fully below, mantle assembly 28 and pilot
assembly 30 are cantilevered from housing 56 by mounting them on
mantle stud 60 and pilot tube 62, respectively, and the material
from which housing 56 is integrally formed is chosen for its
frequency response and oscillatory damping characteristics.
Preferably, housing 56 is formed of a plastic such as
Delrin.TM..
Mounted within housing 56 and adjacent front wall 58 is a plate
member 72 having an internally threaded circular sleeve portion 74
projecting forward of an annular shoulder 76. An annular groove 78
is formed in shoulder 76. Plate member 72 also includes a
rearwardly extending cylindrical portion 80 having a longitudinal
groove 82 formed on the external face thereof. Plate member 72 is
disposed within housing 56 such that sleeve portion 74 mates within
hole 64, whereupon grooves 78 and 82 define a passageway leading
around cylindrical portion 80 to holes 65 and 66.
An externally threaded cylindrical nut 84, having a stepped bore
longitudinally therethrough so as to present an annular shoulder
86, is mated within circular sleeve 74 of plate member 72.
Opposed to plate member 72 is a generally cup-shaped second stage
diaphragm 88 having a forwardly projecting annular sidewall 90 and
a centrally protruding guide portion 92. Guide portion 92 is
provided with a threaded blind hole 96 and an annular shoulder 94.
Diaphragm 88 is nested within plate 72, such that sidewall 90 is in
abutment with cylindrical portion 80 and guide portion 92 projects
through the stepped bore of nut 84.
A screw 100 mates with threaded hole 96 and thus forms an extension
of guide portion 92. A coil spring 98, positioned between shoulders
86 and 94, biases diaphragm 88 to the right as viewed in FIG. 2,
the spring compression being adjustable via nut 84. A circular
bearing pad 102 is mounted in a recess provided on the rearward
face of diaphragm 88.
A pin retainer member 104 having a rearwardly projecting annular
sidewall 106 and a central throughgoing hole 108 encircled by a
valve seat 110 serves to separate first and second stages 52 and
54. As shown in FIG. 2, the dimensioning of plate member 72 and
diaphragm 88 is such that a chamber 112 is formed between the
opposing faces of diaphragm 88 and pin retainer member 104. Chamber
112 is in fluid communication with holes 65 and 66 through grooves
78 and 82.
A generally cup-shaped first stage diaphragm 114 having a
projecting central portion 116 with an annular flange 118
surrounding a throughgoing hole 120 of stepped diameter is nested
within pin retainer member 104.
A valve member 122 having forward and rearward extending stem
portions 124 and 126, respectively, a valve face 128 and an annular
flange 130 is disposed such that forward stem portion 124 projects
through hole 108 to contact bearing pad 102, while rearward stem
portion 126 is positioned within hole 120. A coil spring 132
positioned between flanges 118 and 130 serves to bias valve member
122 forward such that valve face 128 abuts valve seat 110 and, at
the same time, urges diaphragm 114 rearward.
A press-fitted end cap 134 seals regulator housing 56. End cap 134
includes a fuel intake port 136 and a central throughgoing threaded
plug 138 provided with a valve seat 140, which coacts with a second
valve face 142 provided on the rearward face of diaphragm 114
surrounding hole 120. Rotation of plug 138 determines the contact
force between valve seat 140 and valve face 142.
In operation, regulator assembly 26 provides fuel in a gaseous
state, regardless of orientation and over the entire range of
operating temperatures, the pressure of gas supplied being limited
to a predetermined value. Additionally, the fuel flow is terminated
when the tank pressure falls below a predetermined level, and may
also be positively shutoff.
In manufacture, first stage regulator 52 is adjusted by advancing
or withdrawing plug 138, to adjust the contact force between valve
face 142 and valve seat 140 and thereby provide for a one psi
pressure difference between intake aperture 136 and the interior of
first stage regulator 52 (i.e., the pressure to the left of
diaphragm 114, as viewed in FIG. 2). In other words, the contact
force between valve face 142 and valve seat 140 (i.e., the biasing
force exerted by spring 132 when the valve is in a fully closed
position) is adjusted to correspond to a one psi pressure
difference between the gas pressures acting on the forward and
rearward faces of diaphragm 114. Thus adjusted, the valve will
remain closed (i.e., valve face 142 will remain in contact with
valve seat 140) whenever the pressure to the left of diaphragm 114
is equal to or greater than one psi less than the prevailing
pressure within fuel chamber 24. Conversely, should the pressure
within first stage regulator 52 fall below this predetermined level
of fuel chamber pressure less one psi, diaphragm 114 will quickly
move leftward, admitting more high pressure gas from fuel intake
port 136 past valve face 142 and valve seat 140, through hole 120,
between stem 124 and hole 120 to raise the first stage pressure
(i.e., the pressure to the left of diaphragm 114) to the desired
level of fuel supply tank pressure less one psi.
The preferred one psi pressure difference has been chosen to assure
complete evaporation of isobutane fuel over the entire range of
ambient temperatures to which the flashlight might be exposed, down
to that temperature at which the gas pressure within the supply
tank falls below one psi. Below that temperature, the first stage
valve remins closed since the minimum pressure differential of one
psi required to open the first stage can no longer be provided. Of
course, a different pressure drop can be chosen. However, a smaller
pressure drop tends to make the regulator work less reliably,
whereas a larger pressure drop further limits the operating range
at low temperatures.
In addition to assuring complete fuel evaporation, the
above-described construction and adjustment of first stage
regulator 52 provides a low pressure cutoff feature. For example,
if the regulator is adjusted to provide for a one psi pressure
drop, then passage of fuel into first stage regulator 52 will be
inhibited whenever the pressure in fuel chamber 24 falls below one
psi. Without this first stage feature, liquid fuel will enter the
regulator whenever an attempt is made to operate the flashlight in
an inverted position at such a low temperature that the supply tank
pressure is at or below that pressure which the regulator calls for
(e.g., 7 or 8 psi). Passage of liquid fuel will cause blockage of
the small orifice designed to feed the gaseous fuel to the mantle.
Moreover, the regulating function of the regulator is negated when
the flashlight is subsequently exposed to a higher temperature.
Second stage regulator 54 is adjusted by rotation of nut 84 to vary
the bias exerted by spring 98 on diaphragm 88. In practice, it has
been found preferable to limit the pressure of gas in chamber 112
to be on the order of seven to eight psi. Properly adjusted, gas
pressures in chamber 112 less than such desired pressure exert
insufficient force on diaphragm 88 to overcome the force of spring
98, whereupon rightward movement of diaphragm 88 displaces valve
member 122 rearward to increase the gaseous fuel flow through hole
108 past stem 124. Conversely, higher than desirable gas pressures
in chamber 112 occasion a forward movement of diaphragm 88 and an
accompanying decrease of the gas flow through hole 108.
On/Off Switch Assembly
Referring now to FIGS. 4 and 5, on/off switch assembly 27 includes
an on/off switch 144 having recessed bearing slots 146,146 and a
raised camming surface 148. Switch 144 is mounted within an opening
150 in housing portion 12 of the flashlight housing assembly.
Opening 150 is provided with bearing extensions 152,152 of reduced
thickness dimensioned to engage bearing slots 146,146 and thereby
provide for reciprocal sliding movement of switch 144.
A lever 154, rotatable about a pivot pin 156 and having a cam
following surface 158 and regulator claws 160,160, is disposed
inside housing portion 12 and adjacent switch 144. Pin 156 is
carried on arcuate bearing surfaces 70,70 formed on cantilevered
standards 68,68 described above.
A coil spring 162 is positioned within a spring cage 164 which is
formed within lever 154. Spring 162 bears against the inside wall
of housing portion 12 and biases lever 154 in a clockwise direction
as viewed in FIG. 4, about pin 156 to the position indicated in
phantom.
The stem of screw 100 is disposed between claws 160,160 and is free
to move with respect thereto. However, the head of screw 100 is too
large to pass between claws 160,160.
When switch 144 is aligned in its forwardmost (or "off") position,
lever 154 is biased by spring 162 in a clockwise direction to the
position shown by broken lines in FIG. 4. In such a configuration,
claws 160,160 engage the head of screw 100 and urge both screw 100
and diaphragm 88 to their forwardmost range of travel. As a result,
the force exerted by bearing pad 102 on valve stem 124 is
insufficient to overcome the forward biasing effect of spring 132,
and valve face 128 and valve seat 110 remain firmly in contact,
such that the flow of gas from first stage 52 to second stage 54 is
prevented.
To initiate gas flow, switch 144 is moved rearward to its "on"
position, thereby rotating lever 154 to the solid line position
shown in FIG. 4 and removing the restraining effect exerted by
claws 160,160 on screw 100. This in turn frees diaphragm 88, which
then moves to a position of equilibrium between the forces exerted
on its forward face by spring 98 and the gas pressure exerted on
its rearward face.
Mantle Assembly
Referring now to FIG. 6, mantle assembly 28 includes an orifice
holder 168, a first tube 170 and a second tube 172, which are
coaxially mated to form an elongated structure. An orifice housing
174 carrying an orifice plate 176, is mounted within orifice holder
168. Orifice plate 176 is provided with a small throughgoing
orifice having a diameter of approximately 1.2 to 1.4 mils. The
rearward portion of orifice holder 168 is provided with a
counterbore 180 dimensioned to be press-fit over mantle mounting
stud 60, such that mantle assembly 28 is secured, in a cantilever
fashion, to regulator assembly 26.
Orifice holder 168 is additionally provided with a forwardly
extending sleeve portion 182, adapted to receive an enlarged radial
portion 184 of first tube 170, which snugly mates therein in a
press-fit fashion.
The radial dimensioning of first and second tubes 170 and 172 is
such that relative axial movement therebetween is possible, and
shock absorbtion in the axial direction is provided by an axial
shock absorbtion assembly 185, which acts to bias this relative
axial movement.
First tube 170 is provided with a portion of reduced external
diameter, thus forming two annular bearing surfaces 186 and 188.
Forward and rearward split collars 190 and 192 encircle first tube
170 and are provided with outstanding annular flanges 194 and 196,
respectively, which abut surfaces 186 and 188 and are limited in
their range of axial movement thereby. A coil spring 198 positioned
between flanges 194 and 196 biases split collars 190 and 192 apart
from one another and against surfaces 186 and 188.
The rearward portion of second tube 172 is also provided with an
outstanding annular flange 204, which abuts flange 194 of split
collar 190. A four-pronged spring clip 199 (see FIG. 1), two prongs
of which are depicted by reference numerals 200 and 202 in FIG. 6,
serves to contain spring 198 and complete the assembly.
The most forward section of first tube 172 is provided with a
tapered portion 206 to which mantle 34 is shrunk-fit or otherwise
attached. Preferable, mantle 34 is attached as taught in the
above-identified application of Walter J. Diederich entitled "Gas
Mantle Technology".
The structure of mantle assembly 28, in particular the structure of
orifice holder 168, first tube 170 and second tube 172, generally
defines a conduit for the mixing and supply of an air/gas mixture
to mantle 34. In this regard, orifice holder 168 is constructed
with an annular air inlet 210 surrounding counter bore 180 and an
expansion chamber 212, which interconnects with air inlet 210
through a plurality of apertures. Inlet 210 is disposed rearward of
partition 50, as shown in FIG. 1, and is thus supplied with primary
air via primary air inlet ports 51.
Mounted within sleeve portion 182, immediately forward of orifice
plate 168, is a holder 216 having a tapered inlet passage 218 and
enclosing a deflection structure 220. Deflection structure 220,
shown in more detail in FIG. 7, includes a bullet-nosed forward
portion 222 surrounded by radially extending deflection vanes
224.
Deflection surfaces 226 and 228 provided on deflection structure
220 and holder 216, respectively, serve to twice reverse the flow
of the air/gas mixture, while expanding the mixture is an outward
radial direction, thereby promoting thorough mixing.
As seen most clearly in FIG. 6, the dimensioning of holder 216 and
deflection structure 220 is such that deflection structure 220 is
maintained concentrically within holder 216 by vanes 224, e.g., by
press-fitting, and the resultant subassembly is retained in a
press-fit fashion within radial portion 184.
The elongated cantilevered mounting structure formed by
press-fitting counterbore 180 over mantle mounting stud 60 has been
found to be effective in isolating mantle 34 from transverse shock
forces. Such transverse shock forces produce an oscillatory motion
of mantle assembly 28, the extent and duration of which depend to a
large extent on the material chosen for regulator housing 56.
Various plastics such as Delrin (TM) have frequency response and
damping characteristics which have been found to make them good
choices for construction of regulator housing 56.
Shock absorbtion assembly 185 permits mantle assembly 28 to undergo
both axial elongation and compression in response to shock forces
in either axial direction. Axial compression is effected by
relative rearward movement of second tube 172 and split collar 190
against the biasing force exerted by spring 198. Axial elongation
is effected through relative forward movement of second tube 172,
spring clip 199 and split collar 192, again against the resistance
of spring 198.
FIG. 8 shows an even more preferred embodiment of mantle assembly
28 in an unstressed state. Generally, an orifice holder 306 is
coaxially press-fit with a first tube 308, into which is slidingly
mated a second tube 310. Second tube 310 has a rearward outstanding
flange 312 which, in the neutral position shown in FIG. 8, abuts an
annular shoulder 314 formed on the inner surface of first tube 308.
Second tube 310 also has a forward outstanding flange 316 which
abuts a knuckle member 318 of generally semispherical shape.
Knuckle member 318 has a forwardly extending tube portion 320 which
snugly mates with a mantle mounting tube 322 upon which is mounted
mantle 34. Knuckle member 318 is also provided with a throughgoing
rearwardly flared hole 324.
A generally cylindrical cage 326 has a knuckle socket 328 formed in
its forward portion and longitudinal slots 330 and 332 cut in its
rearward periphery. A collar 334 slidingly surrounds first tube 308
and, in an unstressed state, abuts an annular shoulder 336 formed
thereon. Screws 338 and 340 project through slots 330 and 332,
respectively, and engage threaded holes provided in collar 334. A
coil spring 341 extends between flange 316 and collar 334.
Orifice holder 306 encloses a holder 342, a deflection structure
344, a orifice housing 346 and an orifice plate 348 which are
substantially similar to the corresponding elements described above
with respect to FIGS. 6 and 7.
Fuel is supplied through a gas passageway 350 to an expansion
chamber 352 forward of orifice plate 348, and a number of radially
disposed air intake ports 354 are provided in orifice holder 306
which connect with expansion chamber 352. A threaded portion 356 is
disposed immediately adjacent air intake ports 354. An internally
threaded collar 358 mates with threaded portion 356 and is
adjustable with respect thereto to create an air gap 360, the size
of which determines the intake of primary air through air intake
ports 354.
A threaded extension 362 on the rearmost portion of orifice holder
306 secures mantle assembly 28, in a cantilevered fashion, to front
wall 58 of regulator housing 56.
The embodiment of mantle assembly 28 shown in FIG. 8 reduces the
axial and transverse shock forces transmitted to mantle 34 due to
the provision of a biased knuckle joint in the mantle mounting
structure.
FIG. 9(a) shows the knuckle joint in its nominal unstressed
position, with flange 312 abutting shoulde4r 314, collar 334
abutting shoulder 336 and screws 338 and 340 disposed at the back
of slots 330 and 332.
In FIG. 9(b), the knuckle joint is shown in a flexed position in
response to transverse shock forces. In this configuration, the
canting of knuckle member 318 is biased by a slight compression of
spring 341, with second tube 310 moving rearwards with respect to
first tube 308 as shown by the formation of a slight gap between
flange 312 and shoulder 314.
FIG. 9(c) shows the disposition of the various components when the
knuckle joint is fully extended. In this case, as in FIG. 9(a),
flange 312 abuts shoulder 314 and, therefore, further forward
movement of second tube 310 is prevented. However, cage 326 and
collar 334 have moved forward together as a unit, compressing
spring 341 and creating a considerable gap between collar 334 and
shoulder 336.
In FIG. 9(d), the knuckle joint is shown in its fully compressed
state. Here second tube 310 and cage 326 have both been translated
rearwards with respect to first tube 308, creating a significant
gap between flange 312 and shoulder 314. Additionally, screws 338
and 340 are, in the fully compressed state, disposed at the forward
edges of slots 330 and 332.
Pilot Assembly
Referring now to FIG. 10, pilot assembly 30 generally includes a
pilot stem 230 and a holder 232 and, referring to FIG. 2, is
cantilevered from regulator assembly 26 by a press-fit of the
rearward portion of stem 230 into counterbore 67 at the forward end
of pilot tube 62. Counterbore 67 terminates in an annular pilot
valve seat 236 surrounding hole 66. A pilot valve seal 328 is
mounted in a valve seal retainer 240 constructed at the rearward
portion of pilot stem 230.
An O-ring 242 mounted in an annular groove provided on stem 230 and
positioned within counterbore 67 serves to seal the valving
mechanism. The forward portion of stem 230 is press-fit within
holder 232 and is provided with a counterbore 243 for retaining an
orifice housing 244. An orifice plate 246 is mounted in orifice
housing 244 and has a throughgoing orifice with a diameter on the
order of approximately 2.4 mils.
Holder 232 is provided with two spaced, outwardly projecting
annular flanges 250 and 252, which, as discussed below, cooperate
with ignition assembly 32 to control the flow of gas to the pilot
burner tip, and between which are provided a number of
circumferentially spaced air inlets 254. Holder 232 is further
provided with a tapered gas passageway 256 and a deflection
structure 258, which is maintained concentrically within holder 232
by a number of deflection vanes 259.
Inlets 254 connect with an expansion chamber 260 and provide an air
pathway to promote complete combustion of the pilot gas and thereby
substantially prevent the accumulation of soot on lens 44 and other
interior portions of the housing assembly. Reference is made to the
above description of holder 216 and deflection structure 220 as
regards the mixing of the air and gas effected by the portion of
holder 232 forward of inlets 254 and by deflection structure
258.
Ignition Assembly
Ignition assembly 32 is shown in FIGS. 4 and 5 prior to ignition,
and in FIG. 11, the disposition of its various components are shown
immediately following ignition, identical reference numerals being
used in the three figures to identify the same elements.
Ignition assembly 32 is disposed within an opening 262 provided in
housing section 12 and generally includes a pivoted actuation lever
264 biased by a hairpin-shaped leaf spring 266, a flint wheel 268,
a flint cartridge 270 and a valve-actuating lever 272, biased
toward a return position by a coil spring 274.
Lever 264, rotatable about a pivotal axis 276 is provided with an
inwardly projecting portion 278 terminating in an inclined camming
surface 280, which is disposed adjacent a cam following surface 282
provided on one arm of lever 272. The other arm of lever 272
terminates in a bifurcated fork 284, disposed so as to straddle
holder 232 intermediate of annular flanges 250 and 252. Lever 272
pivots about a pivot pin 286 anchored within housing section
12.
A flint cartridge housing 288 is integrally formed as an internal
portion of housing section 12 and has a blind hole 290, wherein is
disposed a flint 292 and a coil spring 294 for biasing flint 292
against flint wheel 268. Housing 288 is also provided with a second
blind hole 295, wherein is disposed coil spring 274, the projecting
end of which encircles a retainer pin 298 provided on the outwardly
projecting arm of lever 272.
Leaf spring 266 terminates in an inwardly projecting spur portion
300, aligned in opposition to the teeth 302 of a sprocket 304
rotationally fixed coaxially with respect to flint wheel 268.
As is most clearly shown in FIG. 4, the distance by which camming
surface 280 is offset from cam following surface 282 is
significantly less than the offset between spur 300 and teeth 302.
As discussed below, such alignment provides delay means for
delaying spark production for a short period of time following the
initiation of pilot gas flow.
Additionally, and referring most particularly to FIG. 5, it will be
seen that pilot assembly 30 and ignition assembly 32, while aligned
substantially vertically with respect to one another, are both
horizontally offset with respect to mantle assembly 28, thereby
minimizing the flint debris which strikes and/or accummulates on
mantle 34.
When switch 144 is moved rearward, fully evaporated gaseous fuel at
a desired and limited pressure is supplied via grooves 78 and 82 to
mantle assembly 28 and pilot assembly 30. The fuel is mixed with
air, traverses mantle assembly 28 and is emitted within mantle 34.
However, within pilot assembly 30, the fuel flow is temporarily
blocked by seal 238 in pilot stem 230.
With fuel thus supplied to mantle assembly 28, the operator
depresses actuation lever 264 of ignition assembly 32, causing
lever 272 to undergo a counterclockwise rotation as viewed in FIG.
4 due to the camming action between surfaces 280 and 282. Due to
the engagement of fork 284 with flanges 250 and 252, holder 232
moves forward relative to stem 230, displacing valve seal 238
forward and permitting the flow of gaseous fuel to the forward
opening of holder 232.
In ignition assembly 32, spark production is delayed for a short
time following the displacement of valve seal 238 to allow time for
pilot fuel to traverse stem 230 and holder 232. Thus, a short time
following displacement of valve seal 238, spur 300 strikes one of
sprocket teeth 302, causing rotation of flint wheel 268 and spark
production. The sparks are directed to the forward opening of
holder 232 to ignite the air/gas mixture now issuing therefrom. The
resulting pilot flame is of sufficient intensity to ignite the
gaseous fuel now enveloping mantle 34.
Mantle 208, now enveloped in burning fuel will become incandescent
and emit a degree of light which will remain substantially constant
for an extended period of time until all the fuel has been
consumed.
In an experimental prototype, having a tank pressure of 30 psi, a
tank capacity of 20 grams of liquid isobutane and a mantle fuel
flow of 1 gram/hr., a light output of approximately 10 lumens was
achieved over a period of approximately 20 hours, yielding a total
light output of approximately 200 lumen-hours. In comparison, a
typical commercial flashlight powered by two carbon/zinc D cell
batteries has a comparable initial light output, but the light
output drops significantly with extended use.
Operation of the flashlight is terminated by the operator effecting
a forward movement of switch 144, thereby mating valve face 128 and
valve seat 110 and cutting off the flow of fuel from first
regulator stage 52.
The foregoing description is by way of illustration and not of
limitation. Various substitutions of equivalents may be made of
those skilled in the art which do not depart from the spirit and
scope of the invention, as set forth in the following claims.
* * * * *